Robot configurations || what are the different types of robotic arm joints || degree of freedom of robotic arm

  

Robot configurations

 

Hi everyone In this blog we will discuss about robot configuration so there are four robot configuration based on movements of joints and link arrangement in that first one is Cartesian Coordinate Configuration so here I had drawn the sketch of gantry robot or also called as rectangular robot it is the simple configuration among all with three prismatic joint the robot functions in rectangular workplace by means of these 3 joint movements these joints allow only in linear motions along three principal axis that is X, Y and Z so it is also called as XYZ robot major application of this configuration include carrying high payloads pick and place material handling used in a sealing handling for plastic moulding 3D printing in CNC machine used in plotter work now we see the advantages this robot is high accurate and high speed the cost is less simple operating procedure only the disadvantage is it required large volume space to operate the next is cylindrical configuration as you can see in this figure it consists of two prismatic joint perpendicular to each other and one revolute joint mounted on rotary axis difference with Cartesian Configuration is one prismatic joint is replace by revolute joint vertical column carries arm assembly that move up and down it also rotate about column the Cylindrical Configuration is used in material handling small assembly task machine loading and unloading next is Spherical Configuration it also called as a polar configuration it has one prismatic joint and two revolute joint first rotary movement occurs about a vertical base axis while second rotary movement is of pivot point about horizontal axis prismatic joint moves wrist rapidly in and out this configuration allow robot to operate in sperical work volume it provide larger work envelope than Cartesian or Cylindrical Configuration next is Articulated Configuration it consists of three revolute joint and one prismatic joint when arm rotates about all three major axis results configuration is Articulated Configuration it is also called as joint arm configuration the arm of this configuration look like a human arm it has two rotary joints shoulder and elbow about their respective horizontal axis the third rotary joint is about vertical base axis 

It is used in manufacturing of steel bridges cutting steel flat glass handling heavy duty robot automation in foundary industries heat resistance robot metal casting spot welding now we see the advantages this robot has high speed it has large working envelope great unique control over welding and painting applications here the only disadvantage is it required dedicated robot controller like PLC next is SCARA configuration it is a special version of a joinetd arm robot whose shoulder and elbow joints rotate about vertical axis instead of horizontal its work envelope is cylindrical and must larger than all other configuration the SCARA acronym stands for selective compliance assembly robot arm or selective compliance Articulated Robot arm the robot was develope under the guidance of Hiroshi Makino the professor at university of Yamanashi the arms of SCARA are flexible in XY axis and rigid in Z axis as you can see in figure it is a representation of XYZ axis of SCARA robot in the XY direction the arm of SCARA robot will be compliant and strong in Z direction this robot is used for various types of assembly operations that is here a round pin can be inserted in a round hole without blinding this robots are faster and cleaner than comparable robot systems now we see the applications of SCARA robot SCARA robot are used for assembly, packaging, machine loading now we see the advantages of SCARA cofiguration it has high speed capabilities perform great in short stroke it contain donult shape work envelope here the disadvantage is the robot requires dedicated robot controller like PLC 

Main types of robotic arms

 There are four main types of robotic arm geometry rectangular cylindrical spherical and jointed spherical robots with rectangular arm geometry use Cartesian coordinates and move linearly along each of the x y and z axes this type of movement is also called 3p geometry where the P stands for prismatic or linear motion this type of geometry is most commonly used with pick-and-place or large overhead mounted robots rectangular arm geometry robots can only move linearly in each direction an overhead crane robot is a good example of this type of motion can move forward and backward left and right and up and down robotic arms that use Cartesian coordinate geometry generate a rectangular work envelope rectangular robotic arms have the simplest geometry and control system and are typically used in material handling operations cylindrical arm geometry robots moved linearly in two directions and rotate in one other since this type of robotic arm moves in two separate prismatic or linear directions and rotates in one direction it's given the designation of  r2p where the R stands for rotational this type of robotic arm is most often used in machine tending assembly material handling and palletizing operations robotic arms with cylindrical geometry move linearly in two directions vertical linear motion is called stroke horizontal linear motion is called reach and rotational motion is called swing cylindrical geometry robots have a cylindrical work envelope the advantages of this type of work envelope is a robotic arm reach that is deep at both the top and bottom of the stroke additionally the robot structure allows for quick movements with high repeatability a smaller use of floor space and a larger payload capacity due to structural rigidity spiracle arm geometry robots can rotate in two directions and move linearly in one and thus are given the designation of two RP the robot has base rotation shoulder rotation and prismatic or linear motion at the arm 

This type of robotic arm is most often used in machine tending material handling welding painting coding and assembly tasks robotic arms with spherical geometry have rotational movement in two directions rotational movement at the base and rotational movement at the shoulder spiracle arm geometry robots also have linear motion in one direction typically the reach of the arm spiracle arm geometry robots have a mostly spherical work envelope at their outer reached but are limited by the linear reach of the arm and the rotation of the shoulder joint the shape of the robots inner work envelope is almost conical and does not become a sphere until the arm extends spiracle arm geometry robots typically have a very long reach and have proven their performance in industrial applications however their high-cost large use of floor space and lack of flexibility compared to jointed spherical arm robots make it hard to justify in most industrial applications jointed spherical arm geometry robots have rotation in three directions use revolute coordinates and are given the designation of 3r they are one of the most popular types of robotic arms and most accurately mimic the movement of the human arm robotic arms with jointed spherical or articulated geometry rotate on at least three axes left and right movements are provided by rotation at the base horizontal movement is provided by rotation at the shoulder and vertical movement is provided by rotation at the elbow except for very close to the body the work envelope of a jointed spherical robotic arm is almost entirely spherical the advantages of this type of work envelope is a robotic arm with very deep reach minimal floor space use and high positioning mobility of the tool end arm due to its mechanical complexity and the complexity of its controller this robotic arm typically comes with a higher hardware cost and requires skilled technicians 

 Degree of  Freedom

 Degree of Freedom in Robot so here I had drawn the sketch of polar type of robot it has 6 degree of freedoms and out of 6 3 motions are of arm and body motions and remaining 3 are wrist motions here as you can see in sketch here is a body and this is a arm here is a wrist and here is a end effector at the end so first 3 motions are of arm and body motions in that first is vertical traverse motion which provides up and down motion to arm with the help of this linkages second is rotational traverse motion it provide rotation to body about vertical axis to the same linkages between body and base third is radial traverse motion it provides extension or retraction movement to arm so these three motions are of arm and body motions so next three motions are of wrist motions so in that first one is pitching this motion provide up and down movement to wrist through the linkages which is shown here second is yawing motion this provide right or left swivel to wrist third is rolling this provide rotation to end effector so these are the 6 degree of freedom in polar type of robot. 

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